Definition of Postpartum Cardiomyopathy
Postpartum cardiomyopathy (PPCM) is an idiopathic cardiomyopathy presenting with heart failure secondary to left ventricular systolic dysfunction towards the end of pregnancy or in the months following delivery, where no other cause of heart failure is found—it is a diagnosis of exclusion with ejection fraction nearly always reduced below 45%. 1
Core Diagnostic Criteria
The Heart Failure Association of the European Society of Cardiology Working Group (2010) provides the most clinically applicable definition, which includes: 1
- Timing: Heart failure develops toward the end of pregnancy or in the months following delivery 1
- Left ventricular dysfunction: Ejection fraction nearly always <45% 1
- Exclusion diagnosis: No other identifiable cause of heart failure 1
- Left ventricular size: May NOT be dilated (distinguishing it from traditional dilated cardiomyopathy) 1
Traditional vs. Contemporary Definitions
The National Heart Lung and Blood Institute/Office of Rare Diseases Workshop (2000) established more rigid criteria that include: 1
- Specific timeframe: Last month of pregnancy or within 5 months postpartum 1
- Absence of recognizable heart disease prior to the last month of pregnancy 1
- Echocardiographic thresholds: LVEF <45%, fractional shortening <30%, or LV end-diastolic dimension >2.7 cm/m² body surface area 1
However, the ESC Working Group notes these rigid timeframes and echocardiographic cutoffs may be arbitrary and lead to under-diagnosis of PPCM. 1 Some patients present beyond 5 months postpartum but are excluded from studies despite having the same condition. 1
Key Distinguishing Features
PPCM is distinct from other forms of heart failure despite resembling dilated cardiomyopathy phenotypically: 1
- Rapid progression: Can deteriorate to end-stage heart failure within days 1
- High recovery rate: Spontaneous and complete recovery of ventricular function occurs in approximately 50% of cases—unusual in other cardiomyopathies 1
- Not pre-existing disease: Not aggravation of underlying dilated cardiomyopathy by pregnancy-mediated volume overload 1
Important Clinical Caveat
Genetically transmitted dilated cardiomyopathy may manifest in the same time interval and is not distinguishable from PPCM. 1 Up to 20% of PPCM cases may have a genetic contribution, particularly titin truncating variants. 2 This overlap creates diagnostic uncertainty about whether some cases represent true PPCM or familial dilated cardiomyopathy unmasked by pregnancy's hemodynamic stress. 1